Security experts are urging Microsoft and Juniper to patch a year-old IPv6 vulnerability so dangerous it can freeze any Windows machine on a LAN in a matter of minutes. The vulnerability was initially discovered in July 2010 by Marc Heuse, an IT security consultant in Berlin. Microsoft has downplayed the risk because the hole requires a physical connection to the wired LAN. The hole is in a technology known as router advertisements, where routers broadcast their IPv6 addresses to help clients find and connect to an IPv6 subnet.”]